SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e98e0744726d97c711150e9a41dc15211ff0b446bf8adfdf929dd0d1d87955af' 
  AND token = 'grhg/8g3ocMShhvwQrQ1GQplj+BwygD8u0Vq5idcmE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}